16
Sep

Common Mistakes in Designing MSE Wall with Finite Element Method

Written by Gouw Tjie Liong, Ir., M.Eng, ChFC, PhD. Posted in Geotechnic, GTL Paper, Publication, Technical Paper & Presentation (Others)

Abstract:  Fast computer processors have made complicated engineering computation techniques, such as finite element method, that was once require hours and hours of computing time, has now been made possible to run all the computation in less than an hour. Since the early 2000s, the availability of commercial geotechnical finite element software combined with faster, smaller, and cheaper notebook computer has made finite element method more accessible to many engineers. However, it is very often the engineers learn just how to operate the software through the tutorial manual without really understand the underlying geotechnical engineering knowledge, they do not realize the old saying: “Garbage in garbage out”. This paper, albeit may not complete, tries to elaborate the common mistakes found in applying the finite element geotechnical software in designing geosynthetics mechanically stabilized earth wall. It does not consider the construction process of the reinforced soil wall where the fill is being built up, during which most of the geogrid strain is developed.

Download full paper: GTL-2018-11th ISG-Seoul-FEMonMSEDesign-S11-07

13
Nov

HIGH HYBRID REINFORCED SOIL SLOPE AS RUNWAY SUPPORT – A CASE STUDY

Written by Gouw Tjie Liong, Ir., M.Eng, ChFC, PhD. Posted in Geotechnic, Technical Paper & Presentation (Others)

Abstract: The use of hybrid Reinforced Soil Slopes combining anchored gabion units and high strength geogrids for infrastructures development is growing in Indonesia. Hybrid RSS are considered a valid and competitive alternative to other traditional earth retaining structures. Despite this growth, civil engineers and construction companies are not yet familiar with the related design and construction aspects. This paper intends to share the Author’s experience regarding the design and the construction of the first stage of a 25 m high hybrid RSS for the new touristic airport at Central Sulawesi, Indonesia. It is worth to note that the RSS was built on soft and weathered clay shales and cohesive backfilling materials were used as part of the reinforced soil mass. This paper aims to present the main technical issues related to the project, the design process, which was carried out using both FEM and Limit Equilibrium method software, and the relevant construction aspects.

Download for full paper: 161107-11-gtl-6th-arc-on-geosynthetics

 

28
Apr

Can Plaxis 2D Model a Laterally Loaded Pile?

Written by Gouw Tjie Liong, Ir., M.Eng, ChFC, PhD. Posted in Geotechnic, Note and Discussion

Someone have modeled a pile for lateral loading in PLAXIS 2D software 
he asked: In the output file, one table we can check for the results.
Could anyone please tell me what is meant by Nmin,Qmin,Mmax ?

Answer:  Old version of Plaxis 2D definitely CANNOT be used to model the laterally loaded pile. In the newest version there is a pile element. But even with this element provided, it is not for calculation of laterally loaded pile. It is a 3D problem, analysis sholud be done in Plaxis 3D. 
Q, N, M refers to shear, normal (axial) and moment.

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